Molecular Dynamics; Sintering; Nanostructured Materials; Flame Aerosol Reactors
Fujiwara Kakeru, Pratsinis Sotiris E. (2018), Single Pd atoms on TiO 2 dominate photocatalytic NO x removal, in Applied Catalysis B: Environmental
, 226, 127-134.
Spyrogianni Anastasia, Karadima Katerina S., Goudeli Eirini, Mavrantzas Vlasis G., Pratsinis Sotiris E. (2018), Mobility and settling rate of agglomerates of polydisperse nanoparticles, in The Journal of Chemical Physics
, 148(6), 064703-064703.
Goudeli Eirini, Pratsinis Sotiris E. (2017), Surface Composition and Crystallinity of Coalescing Silver–Gold Nanoparticles, in ACS Nano
, 11(11), 11653-11660.
Kelesidis G. Goudeli E. and Pratsinis S.E. (2016), Flame synthesis of functional materials and devices: Surface growth and aggregation, in Proceedings of the Combustion Institute
, 36(1), 29-50.
Fujiwara K. Pratsinis S. E. (2016), Atomically dispersed Pd on nanostructured TiO2 for NO removal by solar light, in AIChE J.
, 63(1), 139-146.
Goudeli E. Eggersdorfer M.L. and Pratsinis S.E. (2016), Coagulation of Agglomerates Consisting of Polydisperse Primary Particles, in Langmuir
, 32(36), 9276-9285.
Goudeli E. Eggersdorfer M.L. and Pratsinis S.E. (2016), Agglomeration with polydisperse primary particles in the free molecular regime, in Langmuir
, 32, 9276-9285.
Goudeli E. and Pratsinis S.E. (2016), Crystallinity dynamics of gold nanoparticles during sintering or coalescence, in AIChE J.
, 62, 589-598.
Goudeli E. and Pratsinis S.E. (2016), Gas-phase manufacturing of nanoparticles: Molecular Dynamics and Mesoscale Simulations, in Particul. Sci. Technol.
, 34, 483-493.
Fujiwara K. Müller U. Pratsinis S.E. (2016), Pd subnano-clusters on TiO2 for solar-light removal of NO, in ACS catalysis
, 6, 1887-1893.
Goudeli E. Gröhn A.J. and Pratsinis S.E. (2016), Sampling and dilution of nanoparticles at high temperature, in Aerosol Sci. Technol.
, 50, 591-604.
Goudeli E. Eggersdorfer M.L. and Pratsinis S.E. (2015), Aggregate characteristics accounting for the evolving fractal-like structure during coagulation and sintering, in J. Aerosol Sci.
, 89, 58-68.
Goudeli E. Eggersdorfer M.L. and Pratsinis S.E. (2015), Coagulation – agglomeration of fractal-like particles: structure and self-preserving size distribution, in Langmuir
, 31, 1320-1327.
Fujiwara K. Sotiriou G.A. Pratsinis S.E. (2015), Enhanced Ag+ ion release from aqueous nanosilver suspensions by absorption of ambient CO2, in Langmuir
, 31, 5284-5290.
Fujiwara K. Deligiannakis Y. Skoutelis C.G. Pratsinis S.E. (2014), Visible-light active black TiO2-Ag/TiOx particles, in Appl. Catal. B-Environ.
, 154-155, 9-15.
Today there is a better understanding of nanomaterial properties capitalizing a) on basic research in various fields of science and b) on advances in instrumentation and synthetic processes. This has led to new materials with a number of functionalities and potential applications including catalysts, sensors, biomaterials and even nutritional supplements to name a few that our laboratory has contributed. At the same time, however, little is known on how well nanomaterial properties are reproduced during large-scale manufacture of nanomaterials. So their widespread use largely depends on the development of economic and safe routes for their synthesis. Such materials are made primarily by wet or dry phase (aerosol) processes. The latter have distinct advantages for scale-up given the nanostructured commodities (e.g. carbon black, fumed oxides) available at the ton-scale in the market today. The manufacture of these commodities have taught us that the dynamics of aerosol reactors and product nanoparticle characteristics span 10 and 15 orders of magnitude in length and time. So systematic process design requires models for different length and time scales. These models can be distinguished into continuum, mesoscale, molecular dynamics and quantum mechanics ones that are interconnected for multiscale process design. That way the relationship between product properties and process variables can be built on a firm scientific basis. For example, reactor design for nano-oxides relies typically on particle coagulation and coalescence at various temperatures and residence times. Textbook coagulation rates for spherical particles do not hold for agglomerates of the typical fractal-like nanostructured materials. So, coagulation of nanoparticles with a rapidly evolving structure may result in a) hard agglomerates that are attractive in catalysis and electronics or b) soft agglomerates that are attractive in nanocomposites and liquid suspensions. Such a process can be followed quantitatively by continuum models using mesoscale simulations that describe restructuring of agg(lomer/reg)ates with a nanoparticle coalescence rate from molecular dynamics. Such simulations will be compared systematically to aerosol and material measurements in our and other laboratories.A further focus of this project is the crystallization dynamics of aerosol-made nanoparticles. Control of crystallinity is not as well understood as that of the various nanomaterial sizes. In fact, crystallinity is controlled rather empirically in practice. For example, Al-doping is used to lock rutile formation in gas-phase manufacture of pigmentary titania (a 3-billion dollar world-wide business). After all, the performance of many nanomaterials is often related to their crystal structure. So molecular dynamics will be applied to understand grain boundary mobility, structure and sintering of nanomaterials from first principles and compare with pertinent experimental data. This may help to design crystal phase composition and size which can affect also nanomaterial morphology. This project will assist the education of PhD students specializing in nanoparticle processing and expose BSc/MSc students to fascinating engineering science impacting a number of applications. Results will be presented at international conferences and submitted to refereed journals.